Physics crunch: Time to boost the energy?

If the theory of supersymmetry addresses one of the standard model's central problems – the weakness of gravity compared with the other fundamental forces – the extra particles it predicts should have relatively low masses. Many people were sanguine when the Large Hadron Collider was switched on that signs of supersymmetry were just around the corner.

In truth, though, previous accelerator experiments had already pretty much ruled out the simplest versions of supersymmetry. The no-show of low-energy particles at the LHC has finally done for them. If supersymmetry is to do all it is supposed to do, it must have a more subtle, complex form involving particles at higher mass scales.